Idle speed Chimaera 500

[PelleTVR]

Dear All,

I try to understand an idle speed problem with my Chimaera 500:

When going into idle (when changing gears) idle speed remains at 2.000 rpm. When stopping the car idle speed remains at 2.000 rpm but after a while idle speed goes down to around 1.000 rpm, idle speed starts “sawing”, goes further down to around 800, then engine stops. Restart no problem. All in hot conditions.

Stepper is new, temperature sensor is new.

I checked the engine datas by using the Rover Gauge Software (engine hot, idle):

1. Throttle position 7%
2. Idle bypass position 21%
3. Lambda fuel trim (odd) 100%
4. Lambda fuel trim (even) 100%

Now it´s your turn, every hint is very much welcome.

Thank you!
Ralph

[blitzracing]

You dont say when you take the readings- but if its at the correct idle the throttle pot and idle bypass are not far out. You don't say if the fuel trims are the short or long term plus or minus- but either way 100% is wrong but this is not the idle issue. What's the speedo reading doing when the car is still and the idle high? What is the target idle speed when the tick over is too high?

[PelleTVR]

Hi,

thanks for your reply.
Lambda fuel trim (both, odd and even) +100%, I have in mind "short term" (can't check it, Iam not at home. Btw: what does it mean, short and long term?). Speedo = 0 .
When starting the car and just let the engine run idle speed seems to be correct around 1000 rpm. When the engine starts to be hot idle speed begins to "saw", after a while the engine stops. I did the measurement in the garage, not while driving.
Normal idle speed should be appr. 900 -1000 rpm.
Does it help? Thanks, looking forward for every idea!

Ralph

[blitzracing]

id suspect you have an air leak then- this will make the idle very unstable as it makes the mixture too weak and the ECU will have problems getting it to idle at a fixed RPM. Check the rubber pipework for splits, and that the base idle is correct, and plenum is sealed OK.

[PelleTVR]

if it is just an air leak - would be great. Iam going to check it. I'll come back as soon as I have done the check.
Thanks so far, very much appreciated!
Ralph